The invention relates to a method for measuring a parameter depending on the composition of an unknown fluid by means of a flow sensor, in particular by means of a thermal flow sensor comprising a heater arranged between two temperature sensors.
EP 1 426 740 describes a method for measuring a material-dependent parameter, such as a mixture ratio, of a fluid by means of a flow sensor. The fluid is led over a first temperature sensor, a heater and then a second temperature sensor. The temperature difference between the first and the second sensor as well as the temperature of the second sensor are measured. The mixture ratio of the fluid is then calculated by various, fairly complex mathematical transformations.